This is really strange. Everything looks good but at the end it does not work.
That the PCB is working that is proofen.
I also think that the colour of the capacitors do not make any difference but maybe there is some new model that is causing problems.
ntrip is off, like i said earlier, i currently have the simulator turned on. Where do I check for unstable 5v or 12v? I am currently in the house, so obviously not hooked to tractor battery, rather i’m getting 12v from an AC-DC adapter that i had. When I test the voltage from it, it reads 12.38v steady so I would assume that should be ok. Yes it blinks even without the nano on the pcb, in fact right now the led isn’t even glowing, and I have the board powered…
I have also uploaded the Agopen sketch onto an Arduino Uno that I have, and started putting jumper wires from the Uno to the PCB. With the Uno plugged into the computer, Agopen running, I can see the TX and the RX lights blinking on the Uno, until I plug the A4 pin into the PCB. When i plug in the A4 pin, the TX light stops blinking on the Arduino, when I unplug the A4 pin, TX light starts blinking again. This happens if I have the ADS plugged in and also when it is unplugged from the PCB… 
Edit: just discovered that if i plug into A4 on the pcb first, and then A5, after A4 is plugged in, the same thing happens.
Do you have the big 12 v relay put in? Or do you feed 12 v on big 12 v out. Led must light when 12 v is on without nano.
You must recheck those sda scl lines again. (A4 A5)
Do the 5v check again on PCB, no nano or ads.
I do have the relay in, power is coming in on the 12v in not 12v out. Looks like sometimes when i power on the board, the led comes on for a second or two and then goes off. That is without the nano on the board. I’ll have to wait till I’m back home again today to check the rest
By looking at one of your first pictures, I see a piece of wire in the on off holes, that is definitely NOT stable enough for solid contact. It seems that you turn on the big relay but then it goes off again by itself.
Once I get home I will double check that connection, but I do have the wire soldered on…
Well soldered is very fine.
But why unstable 12 v?
Do you have 5v after the 12v to 5v converters? Without nano!
Or did you by accident put them in, wrong way around?
Some converters are bulky at opposite side as “normal” so check marks for pin one!
Checking, checking and rechecking!!! From what I have checked, it seems as if the 5v converters are installed correctly, I had been wondering myself if they were incorrect, but I’m getting 5v at all the right places, and that was without the nano on the pcb. 12 volt coming out of converter is rock solid, relay clicks on when I power up the board, and clicks off when I unplug it, and multimeter does not show fluctuations in voltage. One thing I have discovered is that A5 pin, or SCL, appears to be connected to ground when I do a continuity test between them. It is not clear to me if that is normal or not. From what I understand from the diagram, it looks like they should NOT be connected, but I realize I may be missing something.
Edit: there also seems to be some continuity between A4 and ground -meter reads about 160 ohms.
So I’ve done some more thinking and testing… I took my nano, NOT plugged into the PCB, started Agopen on computer, and verified that there was communication between the nano and Agopen. I then took a jumer wire and went from A5 to GND, and I observed the same behavior that I was seeing when I put the nano on the PCB-the TX/RX lights stopped blinking on the nano. I did this also with the A4 pin, and the same thing happened. So the conclusion that I have come to, is that somewhere on my PCB, the SCL is shorted to GND…but I don’t have a clue where this short would be. I guess I’ll have to start removing components one at a time to isolate the problem??? Maybe I have arrived at the wrong conclusions?? As far as the LED blinking, that is also puzzling to me, but I know I accidently pushed on it and noticed that it bent over somewhat easily, and I stupidly wiggled the thing back and forth out of curiosity, so maybe I damaged it ???
Good test. Only 2 components R1 and R2, so look at your 3 connectors for nano, ads and mma. Solder might run through holes and short between plastic of connector and PCB. It is R1 and R2 you are measuring (each is 330 ohm) desolder one end of both and you might easier find which connector has the short
Good point I hadn’t thought of that. I can just desolder the resistors…
So, long story short, I just decided to buy the parts I needed to build another pcb. Put it all together last night, plugged it into computer with a cheap pot in breadboard four wheel sensor, and it worked beautifully for about a minute. I could turn the pot and observe the wheel angle changing but suddenly the line went flat and the fun was over. Testing with the multimeter again reveals that a4 pin circuit is once again shorting to ground. This leaves me feeling very confused…
All right, I think that I have finally figured out the problem. While I was at work today I all of a sudden thought of something. When I soldered the board, I used some kind of general purpose solder flux and the brush was way too big and I got way too much flux on everything. I got to thinking that maybe that flux was electrically conductive, and was therefore causing shorts between pins on my board. A quick internet search later, I concluded that flux can indeed be conductive. So the next thing I searched for was how to clean flux off of a pcb, and there was a suggestion to use a toothbrush and rubbing alcohol. So this evening I found a toothbrush and got to work. I now have had it connected to the computer for about twenty minutes and seems to be working perfectly… 
So I learned something that was probably very obvious to most everyone else…